Electronic devices powered by our human bodies are within reach for some scientists. Several gadgets are being researched and developed with examples such as sensor studded clothing to give off vital signs and movement signals, a disposable electrocardiogram machine the size of a Band-Aid that monitors a patient's heart, a cell phone implanted in a tooth, contact lenses with heads up displays, and other miniature electronic devices that can plug people into computer and communication networks. Using regular batteries to power these devices is out of the questions, so new ideas are being researched and developed to scavenge energy from the human body.